             "world!" (substring "Hello world!" 6 12))))
 
 (deftest test-substring-3
-    "Check the function zg.utils/substring."
-    (testing "the function zg.utils/substring."
+  "Check the function zg.utils/substring."
+  (testing "the function zg.utils/substring."
         (are [x y] (= x y)
             "Hello world!" (substring "Hello world!" 0)
             "ello world!"  (substring "Hello world!" 1)

            true  (contains "Hello world!" "world!"))))

(deftest test-contains-NPE
    "Check the function zg.utils/contains."
    (testing "the function zg.utils/contains."
        (is (thrown? NullPointerException (contains nil "")))
        (is (thrown? NullPointerException (contains "" nil)))
        (is (thrown? NullPointerException (contains nil nil)))))

(deftest test-starts-with-1
    "Check the function zg.utils/starts-with."
    (testing "the function zg.utils/starts-with."
        (are [x y] (= x y)
            false (startsWith "Hello world!" "hello")
            true  (startsWith "Hello world!" "Hello")

            true  (endsWith "Hello world!" ""))))

(deftest test-ends-with-2
  "Check the function zg.utils/ends-with."
  (testing "the function zg.utils/ends-with."
        (are [x y] (= x y)
            false (endsWith "" "hello")
            false (endsWith "" "Hello")
